In injection molding, a molded product is ejected from the mold by an ejector mechanism inside the mold. The ejector mechanism generally pushes the ejector pin (ejector pin) fixed to the ejector plate in the mold opening direction. Depending on the shape of the product, the ejector pin may be used instead of the ejector pin, in which case the ejector pin is referred to as an ejector core or ejector block.
The number, arrangement, and diameter of ejector pins vary depending on the product shape and materials used. The reason for this is that the load on the ejector pins varies depending on the product shape. Generally, products with shallow ribs require less ejector force, while products with deeper ribs tend to have greater ejector force.
PPE (elastomer) tends to have a larger ejector force than PP resin, which we often use in our molding process.
Higher ejector force = higher mold release resistance, which not only places more load on the molding machine and mold, but also leaves marks on the molded product due to the ejector pins, resulting in defects.
In other words, for mass production, mold release resistance must be kept as low as possible.
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